Summary The goal of this SBIR program is to develop novel small molecule probes and inhibitors targeting a viral non-coding RNA expressed at high levels in all forms of Epstein-Barr Virus (EBV) tumors. EBER1 is a highly conserved, viral-encoded small nuclear RNA expressed consistently at high-levels in all EBV tumors. EBER1 is required for EBV tumorigenesis in mouse models and functionally interacts with ribosomal subunit L22 that has been implicated in the telomerase immortalization and TLR signaling pathways. The project addresses an unmet medical need to detect and treat EBV- associated cancers and related diseases. EBV latent infection is a causal factor in undifferentiated nasopharyngeal carcinoma, endemic Burkitt?s lymphoma, 50% of Hodgkin?s lymphomas, 20% of non-Hodgkin?s lymphomas, NK/T cell lymphoma, 10% of gastric carcinomas, and the majority of post-transplant lymphoproliferative disease. EBV primary infection is the major cause of infectious mononucleosis. EBV infection is also implicated as a causal agent of multiple sclerosis. To date, no viral-specific therapeutic exists for treatment of EBV latent infection, nor are there non-invasive methods to detect EBV latent infection in tumors. EBER1 is among the most abundant and stable nuclear non-coding RNAs expressed exclusively in EBV positive tumors and therefore represents an ideal target for detection and treatment of EBV-specific tumors. We propose to develop novel and safe small molecules that can selectively bind EBER1 and inhibit its interaction with L22. The product that ultimately results from this proposal is a small molecule probe that selectively binds EBER1 RNA, and can be further developed for the detection and treatment of EBV malignancies and associated diseases.